opengl 如何修改纹理的值
用opengl来处理图片，把图片做为纹理来显示，如何来修改纹理的值，比如我要做图像的梯度运算
读取纹理代码如下：
#pragma once #include "stdafx.h" #include "template.h" #include <gl/GL.h> #include <gl/GLU.h> #include <gl/glut.h> #include <gl\glaux.h> #pragma comment( lib, "opengl32.lib" ) #pragma comment( lib, "glu32.lib" ) #pragma comment( lib, "glaux.lib" ) GLfloat xrot; // X Rotation ( NEW ) GLfloat yrot; // Y Rotation ( NEW ) GLfloat zrot; // Z Rotation ( NEW ) GLuint texture[1]; // Storage For One Texture ( NEW ) AUX_RGBImageRec *LoadBMP(char *Filename) // Loads A Bitmap Image { FILE *File=NULL; // File Handle if (!Filename) // Make Sure A Filename Was Given { return NULL; // If Not Return NULL } File=fopen(Filename,"r"); // Check To See If The File Exists if (File) // Does The File Exist? { fclose(File); // Close The Handle return auxDIBImageLoadA(Filename); // Load The Bitmap And Return A Pointer } return NULL; // If Load Failed Return NULL } int LoadGLTextures() // Load Bitmaps And Convert To Textures { int Status=FALSE; // Status Indicator AUX_RGBImageRec *TextureImage[1]; // Create Storage Space For The Texture memset(TextureImage,0,sizeof(void *)*1); // Set The Pointer To NULL // Load The Bitmap, Check For Errors, If Bitmap's Not Found Quit if (TextureImage[0]=LoadBMP("Data/NeHe.bmp")) { Status=TRUE; // Set The Status To TRUE glGenTextures(1, &texture[0]); // Create The Texture // Typical Texture Generation Using Data From The Bitmap glBindTexture(GL_TEXTURE_2D, texture[0]); glTexImage2D(GL_TEXTURE_2D, 0, 3, TextureImage[0]->sizeX, TextureImage[0]->sizeY, 0, GL_RGB, GL_UNSIGNED_BYTE, TextureImage[0]->data); glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MIN_FILTER,GL_LINEAR); glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MAG_FILTER,GL_LINEAR); } if (TextureImage[0]) // If Texture Exists { if (TextureImage[0]->data) // If Texture Image Exists { free(TextureImage[0]->data); // Free The Texture Image Memory } free(TextureImage[0]); // Free The Image Structure } return Status; // Return The Status }